Chair seat



H. F. OLLIS CHAIR SEAT June 5, 1934;

Filed Sept. 7, 1935 clean.

Patented June 5, 1934 UNITED STATES CHAIR SEAT Harry F. Ollis, Ashland,Mass., assignor of onehalf to Daniel F. Shaughncssy, Ashland,

Mass.

Application September 7, 1933, Serial No. 688,487

3 Claims.

The principal object of this invention is to provide a construction ofchair seat preferably accompanied by a cushion of such a nature that thebones of the occupant, that is the pelvis and 5 thighs, or either, canbe supported on a rigid seat with a cushion over it in such a mannerthat there will be no direct support for the said bones from the rigidchair seat itself but this cushion will be concaved out of 1 its normalshape by the weight of the occupant and the support for that part of thebuttocks and legs in which the bones are situated will come from a spaceor spaces bridged by the suspended cushion and not backed up directly bythe hard seat. Other objects of the invention are to provide aconstruction of seat which will be strong and durable and will notinvolve any material expense greater than that ordinarily employed for aseat of a similar character not having the characteristics of this in- 2vention; and to provide a construction for preventing the reactingpressure throughout the area of primary contact between the normal ornatural human seat and the usual hard chair seat, thereby destroying thecause of most of the 5 discomfort arising from the use of ordinarychairs an chair seats. This is accomplished according to this inventionby providing a space in the chair seat which may be in the form of deepchannels, or perforations all the way through the seat, and which arelocated directly under the pelvic and thigh bones of the occupant sothat when sitting on the, chair, a soft cushion/provided on the top ofthe seat will be 99 aved and flexibly suspended in those po rtions underwhich the said bones are located/Said spaces are wide enough to permitthis and narrow enough to prevent the cushion descending too far intothe space or contacting with the bottom of such a channel, whereby aflexible suspended support is provided 40 in parts of the whole seatwith'its cushion over' which these bones are located and they areentirely relieved from any reactive pressure from the hard surface ofthe seat itself and yet they are supported adequately.

Other objects and advantages of the invention will appear hereinafter.

Reference is to be had to the accompanying drawing, in which Fig. 1 is aperspective view of the rigid part of a chair seat constructed inaccordance with'this invention;

' Fig.2 is a side view of the same as indicated by the arrow 2 in Fig. 1with the cushion in position; and

Fig. 3 is a sectional view on the line 3-3 of Fig.1 on enlarged scaleshowing the position of the legs and thighs of the occupant of the seat,and showing the flexing of the cushion.

I have found, after extensive experience in this industry, that noprovision has yet been made to provide" proper and adequate escapementfor; the pressures that are impressed upon certain definitely locatedareas of the human seat in sitting in a chair. Cushions are employed butthey are always backed up by hard unyielding surfaces and they cannotprovide for the escapement'of this pressure as the cushion is quicklyforced to its compression limit. At the areas of greatest protrusion ofthe human seat at which most of the weight of the occupant isnecessarily localized, there shouldbe a truly yielding surface which isnot subject to the above difficulty. I provide a cushion which is notonly soft and resilient, but also elastic and under such mechanicalconditions that the greatest possible amount of its elasticity may beutilized to relieve the body of the reaction that comes from the seat ofthe chair. My chair seat is intended to be used with a cushion in such away that this elasticity can be utilized for the purpose of providing ayielding suspended foundation on which the parts of the human seat inwhich the bones are located can pressure heretofore thought necessary.

Referring to the drawing, the seat may be wood 8 and can be madeperfectly fiat if desired without the necessity and the expense ofproviding shallow. depressions in. it for fitting the human seat. It isprovided with a space or spaces 2 for the relief of the bones mentioned.In the form shown, these spaces are illustrated as extending clearthrough the seat and of a general U shape opening at the front, thusdividing the seat into two parts,- the outside portion 1 and an insideportion 1. as shown or in the form of deep channels so deep that therubber cushion 4 will never touch the bottom of them.

While in the form shown these two parts are not integrally connectedtogether, they are shown as being rigidly connected together by crossbars 3 and the tops of both sections of the seat are located preferablyin the same plane. This seat is used in connection with a' soft flexibleresilient cushion 4 which can be made of any material having thosequalities but I prefer sponge rubber. Preferably it extends throughoutthe area of the rigid seat and at least extends over the spaces 2. Itcan be secured to the seat 1 by any desired means. 1

The spaces 2 can be made 9 x This U shaped space is shown with the twosides slightly diverging toward the front so as to provide a space forthe pelvic bone and two forwardly extending spaces, preferably connectedtherewith, for the thigh bones. The cushion is made of suitablethickness, preferably lying flat on the seat as shown in Fig. 2. When anoccupant seats himself on this chair seat, his pelvis will normally reston the cushion above the rear or transverse part of the space 2 whilethe thighs will extend forward directly over the side spacesconstituting a part of this space 2.

In Fig. 3 the result is indicated. It will be obvious that the weight oftheoccupant will depressthe cushion or concave it'and that part of itwill project down into the spaces both at the rear and along the sides.This space is sufficiently wide to allow the cushion to flex down intoit but not wide enough to permit it to touch the bottom of the channelor' to extend down to the bottom of the chair seat. On account of thegenerally convex contour of the human seat, a moderately narrow linedrawn along the center of this U-shaped space throughout the entirelength thereof will represent the line of primary contact where actualcontact first occurs. In ordinary chair seats, this is also the area ofmajor support and consequently of maximum pressure. The remainder of theactual contact area with the seat will thereby constitute an area ofsecondary contact. Pressures which develop within this latter area of anordinary chair seat obviously will be considerably less severe thanthose that develop in the area .of primary contact, which lies directlybelow in vertical alignment with the large structural bones. Since thenor- -mal pressures which accompany the occupation of a chair seat arethe result of the action of gravity upon the weight of the occupant,they cannot be entirely avoided. The discomfort,

however, which they cause is not entirely de-- pendent on the intensityof the pressure but is influenced largely by the relative sensitivity topressure of the individual area at which they.

occur and the physical and anatomical conditions existing within sucharea.

It is evident that when the line of major support is located directlybelow a large bone, an intense pressure will quickly develop at thatpoint even when a cushion is used, thereby producing a painful squeezingcompressive action. This affects the muscles, nerves, veins and arterieswhich lie directly below the said bone and directly above the said lineof major support. It is this specific and entirely objectionablecondition which at present generally prevails in chair seats that isaVOided b y this invention. By my invention this area of primarycontact, as herein defined, is definitely excluded from the area ofmajor support.

Referring to Fig. 3, the areas enclosed by the dotted circles 5 indicatethe approximate positions of the right and left legs of the occupant.The parts 6 indicate the position of the corresponding respective thighbones. The line of primary contact is at '7 but it is to be noted herethat, although in an ordinary chair seat this is the line of majorsupport, in the present case that is avoided. This area is supported bythe flexible suspended cushion with no solid backing behind it. Areas 8which constitute points of secondary contact and would constitute areasof minor support in an ordinary chair seat in this case constitute theareas of major support and function as such.

It will be seen therefore that the areas of major support of an ordinarychair seat are removed and in place of it a flexible resilient body isplaced under the. leg at this point and the areas of major support arespaced apart at the sides where both the areas are larger and .thepressure is distributed. Therefore there is no serious reactive pressureagainst the legs of the occupant and a really comfortable chair seat isprovided. In this way the pressures incident to the support of theweight of an occupant of my chair seat are transferred to and impressedupon areas of the human seat which'foranatomical reasons are much lesssensitive to pressure and therefore better adapted to sustain themwithout discomfort or injury.

This application is in part a continuation of my copending applicationSerial No. 454,042, filed May 23, 1930:

Although I have illustrated and described only one form of theinvention, I am aware of the fact that modifications can be made thereinby any person skilled in the art without departing from claims.Therefore, I' do not wish to be limited to all the details ofconstruction herein shown and described, but what I do claim is:-

1. As an article of manufacture, a rigid chair seat having a flexiblecushion over the part thereof that directly supports the pelvis andthighs of the occupant, said cushion being co-extensive with the seat,said se'at having a narrow deep space therein of such shape as toreceive thereabove the pelvis and thighs of the occupant to permit thecushion to be flexed thereby into said space a short distance todirectly support the pelvis and thighs from a freely suspended portionof the cushion. 2. As an article of manufacture, a rigid chair seathaving a thick soft flat flexible cushion over the part thereof thatdirectly supports the pelvis and thighs of the occupant, said cushionbeing coextensive with the seat, said seat having a narrow deep spacetherein of such shape as to receive thereabove the pelvis and thighs ofthe occupant to permit the cushion to be flexed thereby into said spacea short distance, to prevent the pelvis and thighs being supporteddirectly by a part of the seat directly below the part of the cushion onwhich-the pelvis and thighs rest.

3. As an article of manufacture, a substantially rigid flat chair seathaving a substantially U- .shaped space entirely through the seat overwhich

